#include<iostream>

using namespace std;
const int N = 1e3 + 5;
long long a[N], b[N];
int dp[N][N];
int main()
{
    int n, m; cin >> n >> m;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 1; i <= m; i++) cin >> b[i];

    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
        {
            if (a[i] == b[j]) dp[i][j] = dp[i - 1][j - 1] + 1;
            else dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
        }
    cout << dp[n][m] << endl;
    return 0;
}